The present invention generally relates to passenger or wheelchair lifts and, more particularly, to an apparatus for locking a wheelchair lift in the stowed position.
As is known in the art, various types of lifting devices are used to move passengers between a lowered level, such as a ground level, and an elevated level, such as the floor level of a vehicle. For example, U.S. Pat. No. 5,445,488 to Saucier et al., the specification and drawings of which are hereby incorporated by reference herein in their entirety, illustrates therein a typical dual parallel arm hydraulic lift, which is reproduced herein as FIG. 1.
The lift L includes a platform 12 that may be used to lift passengers, such as those in wheelchairs, from a ground level to a floor level F of the vehicle V by actuation of hydraulic cylinders 38. When the platform 12 reaches the floor level F, a bridge plate 34, which is pivotally coupled to the platform 12, operates to bridge any gap between the platform 12 and the floor F, thereby allowing smooth transfer of the wheelchair between the platform 12 and an interior of the vehicle V.
When not in use, the platform 12 is folded to a vertical position (the stowed position) such that the entire lift L is disposed within the vehicle V, allowing the doorway D of the vehicle V to be closed. A known problem with such an arrangement is that the hydraulic cylinders 38 will typically drift over time, possibly allowing the platform 12 to come to rest against the inside of the vehicle door. Not only can this produce an annoying rattling during movement of the vehicle, but it can also impede operation of the door.
A solution to this problem is proposed in the ""488 patent by locking a protrusion on the bottom of the bridge plate 34 into a cavity 41 in the vehicle floor F. Interference between the bridge plate 34 (which is attached to the platform 12) and the cavity 41 prevents the stowed platform 12 from drifting outward. This solution is undesirable for a number of reasons, chief among them being the relatively large number of parts required to releasably latch the bridge plate 34.
There is therefore a need for an apparatus that prevents drift of a stowed lift platform, without requiring a large number of parts or a complex interconnection of those parts. The present invention is directed toward meeting this need.
The present invention relates to a wheelchair-lifting platform for transporting a passenger seated in a wheelchair back and forth between a passenger door of a vehicle and the ground, such that the platform can be automatically folded, retracted, secured and stored in the vehicle when not in use and that can be automatically released, unfolded and deployed when in use. One embodiment of the present invention is an automatically folding and unfolding platform having a spring-loaded and dampened latching hook that automatically latches the platform when it is retracted and automatically releases the platform at the start of its deployment cycle. The platform is folded and stored within the vehicle when not in use.
One object of the present invention is to provide an improved wheelchair-lifting platform. Related objects and advantages of the present invention will be apparent from the following description.